Outer premix barrel vent air sweep

ABSTRACT

A gas turbine engine outer premix barrel is disclosed. The outer premix barrel includes a body portion, a barrel portion, and a plurality of vanes. The body portion includes vent air inlets. The barrel portion extends axially aft from the body portion. The plurality of vanes extends axially forward from the body portion. Each vane includes an inward surface located at a radially inner end of the vane, and a plurality of vent passages exiting the vane at the inward surface. Each vent passage is in flow communication with at least one vent air inlet.

TECHNICAL FIELD

The present disclosure generally pertains to gas turbine engines, and ismore particularly directed toward a fuel injector with an outer premixbarrel.

BACKGROUND

Gas turbine engines include compressor, combustor, and turbine sections.Fuel for gas turbine engines may accumulate on or adjacent to injectorsurfaces during gas turbine engine operation, which may lead toauto-ignition or flame holding.

G.B. patent No. 1,320,263 discloses an air swirler for use in the headend of a gas turbine combustion chamber comprising: an annular bodyportion having an upstream face and a downstream face normal to the axisthereof and defining a central hole for accommodation therein of a fuelnozzle, and a plurality of angled blade members disposed about thecircumference of said body and forming slots for the passage of airthere-between, the ratio of the dimension of each blade face between itsleading and trailing edges to the width of the slots being within therange of 1.15 to 1.85. A plurality of air sweeper holes may extendgenerally from the slots to the downstream face of the body portion sothat a portion of the air will flow through the air sweeper holes andsweep the face of the fuel nozzle.

The present disclosure is directed toward overcoming one or more of theproblems discovered by the inventors.

SUMMARY OF THE DISCLOSURE

A gas turbine engine outer premix barrel is disclosed. The outer premixbarrel includes a body portion, a barrel portion, and a plurality ofvanes. The body portion includes vent air inlets. The barrel portionextends axially aft from the body portion. The plurality of vanesextends axially forward from the body portion. Each vane includes aninward surface located at a radially inner end of the vane, and aplurality of vent passages exiting the vane at the inward surface. Eachvent passage is in flow communication with at least one vent air inlet.

A method for overhauling a gas turbine engine injector is alsodisclosed. The method includes removing an outer premix barrel from theinjector. The outer premix barrel includes a barrel and a barrel end.The barrel includes a body portion including vent air inlets, a barrelportion extending axially aft from the body portion, and a plurality ofvanes extending axially forward from the body portion. Each vaneincludes a truncated wedge shape and a plurality of vent passages inflow communication with at least one vent air inlet. Each vent passageexits the vane at an inward surface located at a truncated portion ofthe truncated wedge shape. The barrel end is joined to the barrel at anaft end of the barrel portion. The barrel end includes a cylindricaltube shape. The method also includes separating the barrel end from thebarrel. The method further includes joining a new barrel end to thebarrel with a metal joining process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an exemplary gas turbine engine.

FIG. 2 is a perspective view of the injector of FIG. 1.

FIG. 3 is a cross-sectional view of the injector head of FIG. 2.

FIG. 4 is a perspective view of the forward end of the outer premixbarrel of FIG. 3.

FIG. 5 is a perspective view of the aft end of the outer premix barrelof FIG. 4.

FIG. 6 is an exploded view of the injector head of FIG. 3.

FIG. 7 is a flowchart of a method for overhauling the injector of FIG.2.

DETAILED DESCRIPTION

The systems and methods disclosed herein include a gas turbine engineinjector including an outer premix barrel. In embodiments, the outerpremix barrel includes vanes with a truncated wedge shape and isremovable from the injector head. Each vane includes vent passages atthe inward surface, the radially innermost portion of the truncatedwedge shape. During operation of the gas turbine engine the ventpassages may sweep away fuel that may collect in a low pressure areaadjacent inward surface, which may prevent auto-ignition or flameholding. A removable outer premix barrel may facilitate access to othercomponents within the injector and may facilitate overhaul of the outerpremix barrel.

FIG. 1 is a schematic illustration of an exemplary gas turbine engine.Some of the surfaces have been left out or exaggerated (here and inother figures) for clarity and ease of explanation. Also, the disclosuremay reference a forward and an aft direction. Generally, all referencesto “forward” and “aft” are associated with the flow direction of primaryair (i.e., air used in the combustion process), unless specifiedotherwise. For example, forward is “upstream” relative to primary airflow, and aft is “downstream” relative to primary air flow.

In addition, the disclosure may generally reference a center axis 95 ofrotation of the gas turbine engine, which may be generally defined bythe longitudinal axis of its shaft 120 (supported by a plurality ofbearing assemblies 150). The center axis 95 may be common to or sharedwith various other engine concentric components. All references toradial, axial, and circumferential directions and measures refer tocenter axis 95, unless specified otherwise, and terms such as “inner”and “outer” generally indicate a lesser or greater radial distance from,wherein a radial 96 may be in any direction perpendicular and radiatingoutward from center axis 95.

A gas turbine engine 100 includes an inlet 110, a shaft 120, a gasproducer or “compressor” 200, a combustor 300, a turbine 400, an exhaust500, and a power output coupling 600. The gas turbine engine 100 mayhave a single shaft or a dual shaft configuration.

The compressor 200 includes a compressor rotor assembly 210, compressorstationary vanes (“stators”) 250, and inlet guide vanes 255. Thecompressor rotor assembly 210 mechanically couples to shaft 120. Asillustrated, the compressor rotor assembly 210 is an axial flow rotorassembly. The compressor rotor assembly 210 includes one or morecompressor disk assemblies 220. Each compressor disk assembly 220includes a compressor rotor disk that is circumferentially populatedwith compressor rotor blades. Stators 250 axially follow each of thecompressor disk assemblies 220. Each compressor disk assembly 220 pairedwith the adjacent stators 250 that follow the compressor disk assembly220 is considered a compressor stage. Compressor 200 includes multiplecompressor stages. Inlet guide vanes 255 axially precede the compressorstages.

The combustor 300 includes one or more injectors 310 and includes one ormore combustion chambers 390. Each injector 310 includes an injectorhead 320 (shown in FIGS. 2 and 3), which includes an outer premix barrel330 (shown in FIGS. 3-6). In the gas turbine engine shown, each injector310 is installed into combustor 300 in the axial direction relative tocenter axis 95 through radial case portion 399 of compressor combustorcase 398 or the compressor diffuser case.

The turbine 400 includes a turbine rotor assembly 410, and turbinenozzles 450. The turbine rotor assembly 410 mechanically couples to theshaft 120. As illustrated, the turbine rotor assembly 410 is an axialflow rotor assembly. The turbine rotor assembly 410 includes one or moreturbine disk assemblies 420. Each turbine disk assembly 420 includes aturbine that is circumferentially populated with turbine blades. Turbinenozzles 450 axially precede each of the turbine disk assemblies 420.Each turbine disk assembly 420 paired with the adjacent turbine nozzles450 that precede the turbine disk assembly 420 is considered a turbinestage. Turbine 400 includes multiple turbine stages.

The exhaust 500 includes an exhaust diffuser 520 and an exhaustcollector 550.

FIG. 2 is a perspective view of injector 310 of FIG. 1. Injector 310 mayinclude a flange 317, an injector head 320, a first main gas tube 311, asecond main gas tube 312, a support tube 313, a liquid inlet tube stem314, a liquid inlet tube 354, a pilot stem 316, and a liquid pilot tubeassembly 370. Flange 317 may be a cylindrical disk. Flange 317 includesflange bolt holes 319 for securing injector 310 to gas turbine engine100 at radial case portion 399 (shown in FIG. 1). Flange 317 may alsoinclude handles 318. Fittings 379 such as gas main and liquid mainconnector assemblies may attach to divider blocks, such as main gasdivider block 386, attached to an outer or base surface of flange 317.Liquid and gas fuel sources may be attached to the fittings 379.

Injector head 320 may include an assembly axis 309 (shown in FIG. 3).All references to radial, axial, and circumferential directions andmeasures of injector head 320 and the elements of injector head 320refer to assembly axis 309, and terms such as “inner” and “outer”generally indicate a lesser or greater radial distance from assemblyaxis 309. The center of flange 317 may be offset from assembly axis 309.

FIG. 3 is a cross-sectional view of the injector head 320 of FIG. 2.Referring to FIGS. 2 and 3, injector head 320 may include body assembly321, outer cap 315, outer premix barrel 330, inner premix tube 360,premix barrel cap 324, liquid gallery assembly 340, flow shield 392,retaining ring 355, liquid pilot tube assembly 370, and pilot shroud380. Body assembly 321 may include injector body 322 and gas main shroud323. Injector body 322 may have a disk or cylindrical shaped base with acoaxial hollow cylinder portion extending in the aft direction from thebase. The diameter of the hollow cylinder portion may be larger than thediameter of the base.

Referring to FIG. 3, injector body 322 may include liquid pilot opening326, feed air passages 325, liquid main opening 327, collar counterbore328, and retaining ring recess 329. Liquid pilot opening 326 may becoaxial to injector body 322 and may extend through the base of injectorbody 322 in the axial direction. Feed air passages 325 may also extendthrough the base of injector body 322 in the axial direction. Feed airpassages 325 may be located radially outward from assembly axis 309 andliquid pilot opening 326, and may be located radially inward from aninner surface of the hollow cylinder portion of injector body 322. Inembodiments, injector body 322 includes four feed air passages 325.

Liquid main opening 327 may be located radially outward from assemblyaxis 309 and feed air passages 325, and may be located radially inwardfrom the inner surface of the hollow cylinder portion of injector body322. Collar counterbore 328 is coaxial to liquid main opening 327 andextends in the forward direction partially into the base of injectorbody 322 from the aft side of the base.

Retaining ring recess 329 is an annular recess may be located at the aftend of the hollow cylinder portion of injector body 322. Retaining ringrecess 329 may be threaded or may include a lip or an annular protrusionconfigured to hold retaining ring 355 in place.

Referring again to FIGS. 2 and 3, gas main shroud 323 may have a hollowcylinder shape and may have a ‘C’, ‘U’, or ‘J’ shaped cross-sectionrevolved about injector assembly axis 309. Gas main shroud 323 mayinclude fuel transfer bosses 308. Fuel transfer bosses 308 may bethickened portions or boss structures extending from a radially innerportion of the hollow cylinder shape of gas main shroud 323. Fueltransfer bosses 308 may be formed to include fuel transfer passages. Oneend of the ‘C’, ‘U’, or ‘J’ shape may attach to the hollow cylinderportion of injector body 322 at or near a radially outermost portion ofthe hollow cylinder portion of injector body 322, while the other end ofthe ‘C’, ‘U’, or ‘J’ shape may attach to the base of injector body 322at or near a radially outermost portion of the base. The connection ofthe ‘U’ or ‘J’ shape of gas main shroud 323 to injector body 322 mayform an annular chamber between gas main shroud 323 and injector body322. Injector body 322 and gas main shroud 323 may be brazed or weldedtogether.

Outer cap 315 may be a dome shaped cap that attaches to the bodyassembly 321 at the radially outer surface of gas main shroud 323. Outercap 315 may include multiple holes and passageways.

Referring again to FIG. 2, first main gas tube 311 and second main gastube 312 may extend from the gas main connector assembly (not shown) andflange 317 in the axial direction to fuel transfer bosses 308 (shown inFIG. 3). First main gas tube 311 and second main gas tube 312 may be inflow communication with main gas shroud and the flow transfer holes.

Support tube 313 may connect to flange 317 and gas main shroud 323 ofbody assembly 321. Support tube 313 may extend axially and radiallyinward from flange 317 to body assembly 321 relative to injectorassembly axis 309.

Liquid inlet tube stem 314 and pilot stem 316 may each extend fromflange 317 to injector head 320 in the axial direction. Liquid inlettube stem 314 may be a circular tube and may attach to gas main shroud323. Liquid inlet tube stem 314 may attach to gas main shroud 323 nearor adjacent to where support tube 313 connects to gas main shroud 323.Pilot stem 316 may attach to and may be partially inserted into liquidpilot opening 326 of injector body 322. Liquid inlet tube stem 314 maybe welded or brazed to gas main shroud 323, and pilot stem 316 may bewelded or brazed to injector body 322.

Liquid inlet tube 354 may extend axially through liquid inlet tube stem314 from the liquid main connector and flange 317 to injector body 322and through liquid main opening 327 of injector body 322.

Referring to FIG. 3, liquid gallery assembly 340 may include collar 353,gallery cover 342, liquid gallery 341, atomizers (not shown), andclocking pin 352. Liquid inlet tube 354 may connect to gallery cover342. Collar 353 may be located adjacent gallery cover 342 around the endof liquid inlet tube 354 that attaches or connects to gallery cover 342.Collar 353 may be also located within collar counterbore 328.

Liquid gallery 341 includes gallery body and liquid gallery scroll 343.Liquid gallery 341 may also include atomizer inlets (not shown),atomizer bosses 347, and clocking pin boss 348. Gallery body may be anannular ring or hollow cylinder coaxial to liquid gallery assembly 340and injector assembly axis 309. Liquid gallery 341 is formed to includeliquid gallery scroll 343, an annular channel about the forward radialsurface of gallery body and extending into gallery body. Liquid galleryscroll 343 may be sized to maintain a predetermined velocity of theliquid fuel passing through liquid gallery scroll 343 during operationof the gas turbine engine 100.

In the embodiment illustrated, the cross-section of liquid galleryscroll 343 is an extended half round or rectangle with a semicircle atthe end. Other cross-sectional shapes such as rectangles, squares, andcircles may also be used. The edges of the rectangle and squarecross-sections may be rounded.

Atomizer bosses 347 may extend from the aft radial surface of theannular ring or hollow cylinder shape of liquid gallery 341 in theaxially aft direction. Each atomizer boss 347 may be sized to hold oneatomizer. Each atomizer boss 347 may have a hollow cylinder shape with adiameter smaller than the radial thickness of liquid gallery 341.Atomizer bosses 347 may be equally spaced about liquid gallery 341.

In the embodiment illustrated, a clocking pin boss 348 extends from theaft radial surface of the annular ring or hollow cylinder shape ofliquid gallery 341 in the axially aft direction between two atomizerbosses 347. Clocking pin boss 348 may be shaped similarly to atomizerbosses 347 and may be sized to hold clocking pin 352. Clocking pin 352may have a cylindrical shape. Clocking pin 352 may help align innerpremix tube 360 within injector head 320.

Gallery cover 342 may be an annular ring or hollow cylinder with a ‘C’or ‘U’ shaped cross-section revolved around the axis of liquid galleryassembly 340 which is coaxial to injector assembly axis 309. Gallerycover 342 may include liquid inlet tube boss 349 extending axiallyforward from the annular ring or hollow cylinder shape of gallery cover342. Liquid inlet tube 354 extends into liquid inlet tube boss 349.Collar 353 may be located radially around liquid inlet tube boss 349.

Gallery cover 342 may be sized to fit over the outer and innercircumferential surfaces of liquid gallery 341. The forward radialsurface of liquid gallery 341 may contact gallery cover 342 and form aseal with gallery cover 342. Gallery cover 342 may be brazed or weldedto liquid gallery 341 at the outer and inner circumferential surfaces ofliquid gallery 341.

Flow shield 392 may include an axial portion located radially inwardfrom liquid gallery 341 and a radial portion extending from the axialportion located axially between liquid gallery 341 and inner premix tube360.

Inner premix tube 360 may include transition end 361, middle tube 362,tip end 363, and premix tube inner surface 365. In the embodimentillustrated in FIG. 3, transition end 361 is a hyperbolic funnel thatincludes an annular disk portion 367 and a redirection portion 368 thatcurves toward the axially aft direction from the annular disk portion367. In other embodiments, redirection portion may be formed fromvarious cross-sectional shapes revolved about the axis of inner premixtube 360 that extend radially inward and axially from the annular diskportion 367 to begin the transition from a radial direction to an axialdirection.

Transition end 361 may include outer cylindrical portion 375, retaininglip 364, clocking hole 369, and wipe passages 366. Outer cylindricalportion 375 may extend axially forward from the radially outer part ofannular disk portion 367 in the direction opposite tip end 363. Outercylindrical portion 375 may have a right hollow circular cylinder shape.Retaining lip 364 may extend radially outward from outer cylindricalportion. In the embodiment illustrated, retaining lip 364 also extendsaxially forward. Clocking hole 369 is sized to receive clocking pin 352and aligns with clocking pin 352 when assembled. Transition end 361 mayinclude a thickened or boss portion around clocking hole 369.

Transition end 361 is configured to include wipe passages 366. Wipepassages 366 may extend through redirection portion 368. Wipe passages366 are configured to direct air along premix tube inner surface 365. Inthe embodiment shown, transition end 361 includes 12 wipe passages 366equally spaced thirty degrees apart about transition end 361 extendingaxially through transition end 361. In other embodiments, a differentnumber of wipe passages 366 may be used. Wipe passages 366 are sized andconfigured so that there is no or a minimal pressure drop across thewipe passage 366. Different shapes, sizing, spacing, and configurationsmay also be used.

Middle tube 362 may be welded or brazed to the aft end of transition end361. In the embodiment shown in FIG. 3, middle tube 362 continues thehyperbolic funnel shape of transition end 361. In other embodiments,middle tube 362 may be a conical frustum, a funnel, or formed from across-section with curved outer and inner surfaces revolved about theaxis of inner premix tube 360.

Tip end 363 may be welded or brazed to the aft end of middle tube 362.In the embodiment shown in FIG. 3, tip end 363 includes a curved portion357, a cylindrical portion 358, and a tip face 359. Curved portion 357may continue the hyperbolic funnel shape of transition end 361 andmiddle tube 362 and transitions from the curve of middle tube to ahollow right circular cylinder. Cylindrical portion 358 may be a hollowright circular cylinder extending aft from curved portion 357. Tip face359 extends radially inward from the aft end of cylindrical portion 358and may form an annular disk, the aft end being the axial end ofcylindrical portion 358 distal to transition end 361.

Premix tube inner surface 365 is at least a portion of the outer surfaceof inner premix tube 360. Premix tube inner surface 365 is a revolvedsurface about the axis of inner premix tube 360 that transitions from aradial or an annular ring surface to a circumferential or cylindricalsurface. In the embodiment illustrated, premix tube inner surface 365 isa hyperbolic funnel or a segment of a pseudosphere. In otherembodiments, the radial surface may transition to a cylindrical surfacewith a combination of line segments or curves revolved about the axis ofinner premix tube 360.

In the embodiment illustrated in FIG. 3, retaining ring 355 is anannular ring. Retaining ring 355 is sized to be installed withinretaining ring recess 329. In the embodiment shown, retaining ring 355and retaining ring recess 329 are threaded to secure retaining ring 355to injector body 322. Other retaining or locking mechanisms may be usedto secure retaining ring 355 to injector body 322. Retaining ring 355 isconfigured to secure, retain, or lock inner premix tube 360 withininjector head 320. In the embodiment shown, retaining ring 355 isaxially aft and radially aligned with retaining lip 364, securing innerpremix tube 360 to injector body 322.

Liquid pilot tube assembly 370 may extend axially through pilot stem 316from the pilot connector and through injector head 320. Liquid pilottube assembly 370 may be coaxial to injector assembly axis 309. Pilotshroud 380 may be located radially outward from a portion of liquidpilot tube assembly 370 and located radially inward from inner premixtube 360. Pilot shroud 380 may extend aft from injector body 322.

FIG. 4 is a perspective view of the forward end of the outer premixbarrel 330 of FIG. 3. FIG. 5 is a perspective view of the aft end of theouter premix barrel of FIG. 4. Referring to FIGS. 3-5, outer premixbarrel 330 may include barrel 331, barrel end 332, and premix tube outersurface 339. Barrel 331 may include body portion 337, barrel portion338, and vanes 333. In the embodiment illustrated, body portion 337generally has an annular disk shape. Referring to FIG. 5, body portion337 includes vent air inlets 335 and bolt holes 385. Vent air inlets 335may extend through the annular disk shape in the axial direction. In theembodiment illustrated, vent air inlets 335 extend through the annulardisk shape from an aft radial face of the annular disk shape. Barrelportion 338 may extend axially aft from body portion 337. Barrel portion338 may extend from the aft and radially inner portion of body portion337. Barrel portion 338 may have a hollow cylinder or cylindrical tubeshape. The hollow cylinder or cylindrical tube shape may be tapered. Thetapered cylinder may be the frustum of a hollow cone.

Referring to FIG. 4, vanes 333 may extend axially forward from bodyportion 337. In the embodiment illustrated, vanes 333 are wedge shapedwith the tip of the wedge truncated or removed. The edges of vanes 333may be rounded. Vanes 333 may include other shapes configured to directand swirl air into the premix tube. Each vane 333 may include inwardsurface 387, outer surface 395, contact surface 396, first inlet surface393, and second inlet surface 394. Inward surface 387 is the surface atthe end of each vane 333 and is the radially inner surface of vane 333.Inward surfaces 387 may be the surface located at the truncated portionof the vanes 333. In the embodiment illustrated, each inward surface 387is a circumferential surface. In other embodiments, each inward surface387 may be a flat or rounded surface.

Outer surface 395 may be the radially outer surface of each vane 333,the surface opposite inward surface 387. Outer surface 395 may be flator rounded and may be a circumferential surface. Contact surface 396 maybe the surface distal to and opposite body portion 337. Contact surface396 may face the axial direction extending from inward surface 387 toouter surface 395. Contact surface 396 may contact injector body 322when outer premix barrel 330 is connected to injector body 322.

First inlet surface 393 and second inlet surface 394 may be radialsurfaces on opposite sides of each vane 333. Both first inlet surface393 and second inlet surface 394 may extend from outer surface 395 toinward surface 387. Vanes 333 are spaced apart to form primary airinlets 336. The first inlet surface 393 and the second inlet surface 394of adjacent vanes 333 may form a primary air inlet 336.

Referring to FIGS. 4 and 5, each vane 333 may include vent passages 334,fuel passages 383, fuel supply passages 384, vent air inlets 335, andbolt holes 385. Vent passages 334 may extend partially through each vane333 and exit vane 333 at inward surface 387. In the embodimentillustrated, each vane 333 includes six vent passages 334. A vent airinlet 335 extends into a vane 333 and may extend through body portion337 toward contact surface 396. In the embodiment shown, each ventpassage 334 (examples shown dashed) extend from vent air inlet 335(example also shown dashed) to inward surface 387. Each vent air passage334 is in flow communication with at least one vent air inlet 335.

A fuel supply passage 384 extends axially into each vane 333. Each fuelsupply passage 384 may extend from contact surface 396 towards bodyportion 337. Fuel passages 383 may extend from a fuel supply passage 384to a first inlet surface 393 or a second inlet surface 394, adjacentprimary air inlet 336. In the embodiment illustrated, each vane 333includes six fuel passages 383 located at the radially outer portion offirst inlet surface 393. Each fuel supply passage 384 is in flowcommunication with the fuel passages 383 located on the same vane 333 asthe fuel supply passage 384.

Referring to FIG. 5, barrel end 332 may be joined to barrel 331 at theaft end of barrel portion 338 with a metal joining process such aswelding or brazing. In one embodiment, barrel end 332 is joined tobarrel 331 by electron beam welding. Barrel end 332 may have a hollowcylinder or cylindrical tube shape similar to the shape of barrelportion 338. The hollow cylinder or cylindrical tube shape may betapered. The tapered cylinder may be the frustum of a hollow cone.Premix barrel cap 324 may be welded or brazed to the aft end of barrelend 332 at the outer surface of barrel end 332. Referring to FIG. 3,premix barrel cap 324 may have a ‘C’, ‘U’, or ‘J’ shaped cross-sectionthat is revolved about injector assembly axis 309. Premix barrel cap 324may form an air pocket or channel with barrel end 332.

Premix tube outer surface 339 may include the radially inner cylindricalsurfaces of barrel 331 and barrel end 332. When installed in injectorhead 320 (shown in FIG. 3), premix tube outer surface 339 may be locatedradially outward from premix tube inner surface 365.

FIG. 6 is an exploded view of the injector head 320 of FIG. 3. Referringto FIGS. 3 and 6, outer premix barrel 330 may be secured to bodyassembly 321 with bolts 389 and lock plates 388. Inner premix tube 360may be secured to body assembly 321 by retaining ring 355. In someembodiments, retaining ring 355 is screwed on to body assembly 321.

One or more of the above components (or their subcomponents) may be madefrom stainless steel and/or durable, high temperature materials known as“superalloys”. A superalloy, or high-performance alloy, is an alloy thatexhibits excellent mechanical strength and creep resistance at hightemperatures, good surface stability, and corrosion and oxidationresistance. Superalloys may include materials such as HASTELLOY,INCONEL, WASPALOY, RENE alloys, HAYNES alloys, INCOLOY, MP98T, TMSalloys, and CMSX single crystal alloys.

INDUSTRIAL APPLICABILITY

Gas turbine engines may be suited for any number of industrialapplications such as various aspects of the oil and gas industry(including transmission, gathering, storage, withdrawal, and lifting ofoil and natural gas), the power generation industry, cogeneration,aerospace, and other transportation industries.

Referring to FIG. 1, a gas (typically air 10) enters the inlet 110 as a“working fluid”, and is compressed by the compressor 200. In thecompressor 200, the working fluid is compressed in an annular flow path115 by the series of compressor disk assemblies 220. In particular, theair 10 is compressed in numbered “stages”, the stages being associatedwith each compressor disk assembly 220. For example, “4th stage air” maybe associated with the 4th compressor disk assembly 220 in thedownstream or “aft” direction, going from the inlet 110 towards theexhaust 500). Likewise, each turbine disk assembly 420 may be associatedwith a numbered stage.

Once compressed air 10 leaves the compressor 200, it is diffused andenters the combustor 300. Referring to FIGS. 3 and 4, a portion of air10 travels along path 306 and enters primary air inlets 336 betweenvanes 333 where fuel is added via fuel passages 383. Air 10 and the fuelare mixed and swirled between premix tube outer surface 339 and premixtube inner surface 365.

Referring to FIG. 1, the air 10 and fuel mixture is injected into thecombustion chamber 390 and combusted. Energy is extracted from thecombustion reaction via the turbine 400 by each stage of the series ofturbine disk assemblies 420. Exhaust gas 90 may then be diffused inexhaust diffuser 520, collected and redirected. Exhaust gas 90 exits thesystem via an exhaust collector 550 and may be further processed (e.g.,to reduce harmful emissions, and/or to recover heat from the exhaust gas90).

Referring to FIG. 4, the truncated portion of each vane 333 may create alow pressure area or dead space at or adjacent to inward surface 387,which may cause some of the fuel passing through fuel passages 383between vanes 333 and fuel from the atomizers to collect or accumulateon or adjacent inward surface 387. Fuel accumulated on or adjacentinward surface 387 may cause auto-ignition or flame holding.

Referring to FIGS. 3-5, during operation of gas turbine engine 100, aportion of the air 10 may travel along path 307 and enter vent airinlets 335. The air passes through vent air inlets 335 and exits ventair inlets 335 through vent passages 334. The air exiting vent passages334 may provide a vent air sweep and push or sweep away the fuelaccumulating in the low pressure area or dead space at or adjacent toinward surface 387. Sweeping the fuel out of the low pressure area ordead space may prevent auto-ignition and flame holding, which mayincrease efficiency, reduce emissions, and increase the life of injectorhead 320 including outer premix barrel 330 and inner premix tube 360.

During the lifetime of an injector 310, it may be overhauled. Componentsof injector head 320 including outer premix barrel 330, inner premixtube 360, and liquid gallery assembly 340 may need to be repaired orreplaced. Referring to FIG. 6, outer premix barrel 330, including vanes333, is removed from injector head 320 by removing bolts 389. Innerpremix tube 360 is removed after removing outer premix barrel 330 byremoving retaining ring 355. Removing outer premix barrel 330 and innerpremix tube 360 provides access to liquid gallery assembly 340 (shown inFIG. 3), allowing the repair or replacement of liquid gallery assembly340. Flow shield 392 (shown in FIG. 3) may also need to be removed toaccess liquid gallery assembly 340.

Referring to FIG. 3, liquid gallery assembly 340 may be welded or brazedto injector body 322. In embodiments, collar 353 is brazed into collarcounterbore 328. Liquid gallery assembly 340 is removed from injectorhead 320 by machining out the portions of liquid gallery assembly 340welded or brazed to injector body 322. Providing a removable outerpremix barrel with vanes 333, a removable inner premix tube 360, andaccess to liquid gallery assembly 340 may reduce overhaul costs and mayincrease the life of injectors 310.

During operation of gas turbine engine 100 barrel end 332 of outerpremix barrel 330 and tip end 363 of inner premix tube 360 are adjacentcombustion chamber 390 and exposed to high temperatures. Barrel end 332and tip end 363 may need to be replaced sooner than other portions ofouter premix barrel 330 and inner premix tube 360. Replacing barrel end332 or tip end 363 may reduce repair and overhaul costs of injectors310.

FIG. 7 is a flowchart of a method for overhauling an injector 310. Themethod includes removing outer premix barrel 330 from the injector 310at step 810. Step 810 includes removing bolts 389 that secure outerpremix barrel 330 to injector body 322. Step 810 is followed byseparating barrel end 332 from barrel 331 at step 820. Step 820 mayinclude removing the weld or braze between barrel 331 and barrel end332. Step 820 is followed by joining a new barrel end 332 to barrel 331using a metal joining process. Metal joining processes such as weldingand brazing may be used. In one embodiment, electron beam welding isused.

The preceding detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. The described embodiments are not limited to use inconjunction with a particular type of gas turbine engine. Hence,although the present disclosure, for convenience of explanation, depictsand describes a particular outer premix barrel, it will be appreciatedthat the outer premix barrel in accordance with this disclosure can beimplemented in various other configurations, can be used with variousother types of gas turbine engines, and can be used in other types ofmachines. Furthermore, there is no intention to be bound by any theorypresented in the preceding background or detailed description. It isalso understood that the illustrations may include exaggerateddimensions to better illustrate the referenced items shown, and are notconsider limiting unless expressly stated as such.

What is claimed is:
 1. An outer premix barrel for a fuel injector of agas turbine engine, comprising: a body portion including vent airinlets; a barrel portion extending axially aft from the body portion;and a plurality of vanes extending axially forward from the bodyportion, each vane including an inward surface located at a radiallyinner end of the vane, and a plurality of vent passages exiting the vaneat the inward surface, each vent passage being in flow communicationwith at least one vent air inlet; wherein the body portion includes anannular disk shape; and wherein each vent air inlet extends through theannular disk shape from a radial face of the annular disk shape and intoone of the plurality of vanes towards a contact surface of the vane, thecontact surface facing in an axial direction.
 2. The outer premix barrelof claim 1, wherein each vane is a truncated wedge shape and the inwardsurface of each vane is located at a truncated portion of the vane. 3.The outer premix barrel of claim 1, wherein each vent passage extendsfrom one of the vent air inlets to the inward surface located on thesame vane as the vent air passage.
 4. The outer premix barrel of claim1, wherein the barrel portion includes a hollow cylinder shape.
 5. Theouter premix barrel of claim 1, wherein the plurality of vanes arespaced apart to form primary inlets, and each vane includes a fuelsupply passage extending from a contact surface towards the bodyportion, the contact surface being an axial surface of the vane distalto the body portion, and a plurality of fuel passages on an inletsurface of the vane, adjacent one of the primary inlets, the pluralityof fuel passages being in flow communication with the fuel supplypassage.
 6. A fuel injector of a gas turbine engine, the fuel injectorcomprising: the outer premix barrel of claim 1; a body assemblyincluding an injector body, the outer premix barrel being axiallyadjacent to the injector body and secured to the injector body; and aninner premix tube affixed to the injector body with a retaining ring,the inner premix tube being located radially inward from the outerpremix barrel; wherein a premix tube outer surface including at least aportion of an inner surface of the outer premix barrel, and a premixtube inner surface including at least a portion of an outer surface ofthe inner premix tube form a premix tube.
 7. A gas turbine engineincluding the outer premix barrel of claim
 1. 8. A method foroverhauling the outer premix barrel of claim 1, the method comprising:removing the outer premix barrel from an injector; separating the barrelend from the barrel; joining a new barrel end to the barrel with a metaljoining process.
 9. A gas turbine engine outer premix barrel,comprising: a barrel including a body portion with an annular diskshape, the body portion including vent air inlets extending axiallythrough the annular disk shape, a barrel portion extending axially aftfrom an aft and radially inner portion of the body portion, and aplurality of vanes extending from the body portion opposite the barrelportion, each vane including an inward surface located at an end of thevane and is a radially inner surface of the vane, and a plurality ofvent passages in flow communication with at least one vent air inlet,each vent passage exiting the vane at the inward surface.
 10. The outerpremix barrel of claim 9, wherein each of the plurality of vanes has atruncated wedge shape.
 11. The outer premix barrel of claim 9, furthercomprising a barrel end joined to the barrel at an aft end of the barrelportion, the barrel end including a shape of a frustum of a hollow cone.12. The outer premix barrel of claim 9, wherein each vent air inletextends into one of the plurality of vanes toward a contact surface ofthe vane, the contact surface being distal to and opposite the bodyportion.
 13. The outer premix barrel of claim 9, wherein the pluralityof vanes are spaced apart to form primary inlets, and each vane includesa fuel supply passage and a plurality of fuel passages extending fromthe fuel supply passage to an inlet surface adjacent one of the primaryinlets, the plurality of fuel passages being in flow communication withthe fuel supply passage.
 14. A gas turbine engine, comprising: a fuelinjector including the outer premix barrel of claim 9; a body assemblyincluding an injector body, wherein the outer premix barrel is securedto the injector body with bolts, and an inner premix tube affixed to theinjector body with a retaining ring, the inner premix tube being locatedradially inward from the outer premix barrel.
 15. A method foroverhauling a gas turbine engine injector, comprising: removing an outerpremix barrel from the injector, the outer premix barrel including abarrel including a body portion including vent air inlets, a barrelportion extending axially aft from the body portion, and a plurality ofvanes extending axially forward from the body portion, each vaneincluding a truncated wedge shape and a plurality of vent passages inflow communication with at least one vent air inlet, each vent passageexits the vane at an inward surface located at a truncated portion ofthe truncated wedge shape, wherein the body portion includes an annulardisk shape, and wherein each vent air inlet extends through the annulardisk shape from a radial face of the annular disk shape and into one ofthe plurality of vanes towards a contact surface of the vane, thecontact surface facing in an axial direction, and a barrel end joined tothe barrel at an aft end of the barrel portion, the barrel end includinga cylindrical tube shape; separating the barrel end from the barrel;joining a new barrel end to the barrel with a metal joining process. 16.The method of claim 15, wherein separating the barrel end from thebarrel includes removing a weld from the barrel.
 17. The method of claim15, wherein joining the new barrel end to the barrel with the metaljoining process includes welding the new barrel end to the barrel. 18.The method of claim 17, wherein welding the new barrel end to the barrelincludes electron beam welding.